Soundproof door



' Oct. 17, 1933. B. E. BALDUF 1,931,125

SOUNDPROOF DOOR Filed April 14, 1930 SSheets-Sheet l INVENTOR BY Bea/v0 E. BHL 00R AT'TORNEY Oct. l7, 1933.

B. E. BALDUF SOUNDPROOF DOOR Filed April 14, 1930 3 Sheets-Sheet INVENTOR BEU VO E. BFIL DL/F."

ATToRiE Y y Patented Oct. 17, 1933 SOUNDPROOF DOOR Bruno E. Baldui, Chicago, 111., assignor to United States Gypsum Company, Chicago, 111., a corporation of Illinois Application April 14, 1930. Serial No. 444,011 3 Claims. (01. 20-35) This invention relates to building constructions and has reference more particularly to movable, soundproof partitions, such as doors.

The problem of .preventing the passage of' sound through doors and other movable partitions, has given considerable trouble in the past. Various-types of doors have been sold for this purpose which have been excessively high in cost, ;;,of great weight, or which, are

clumsy to handle andrequire specialhardware for supporting same. One door of this nature is made quite largely of lead and has a weight of 425 pounds. This particular door requires very heavy hinges and a complicated system of bolts and locking devices for holding it flush in contact with the door jamb.

An object of this invention, therefore, is to make a soundproof door, or other movable partition, which is highly effective as a barrier against the transmission of sound from one room to another, and which is exceedingly light in weight and easy to handle.

Another object of the invention is to provide a soundproof door in which ordinary door hardware can be used.

A further object of the invention is to provide a soundproof doorwhich is low in cost of manufacture; also to improve soundproof movable partitions in other respects hereinafter specified and claimed.

Reference is to be had to the accompanying drawings forming a part of this specification, in

which Fig. 1 is a perspective view of my improved soundproof door with parts broken away to disclose the construction,

Fig. 2 is a perspective view of one of the sound absorbing spring clips used in the door construction,

Fig. 3 is an elevation of my door having a considerable thickness, with one of the face panels removed to disclose the constructio Fig. 4 is a sectional view through the door on the line 4-4 of Fig. 3,

Fig. '5 is a sectional elevation through the door on the line 5-5 of Fig. 3,

Fig. 6 is a sectional plan view through the door on line 6-6 of Fig. 3,

Fig. '7 is an elevation of a modified form of thin door, with one of the face panels removed to disclose the construction,

Fig. 8 is a sectional elevation through the door on line 8-8 of Fig. '7, and

Fig. 9 is a sectional plan view through the door on line 9-9 of Fig. 1, showing the door in closed position.

In my improved door construction, two or more panels are provided which are separated by resilient spring clips. These clips are of sufficient flexibility to absorb the impact of sound waves impinging on'the panels, and yet are of sufiicient, structural strength to support the weight of the panels without permitting the panels to comein direct contact with the frame 5 work of the door. The door construction includes thin sheets of metal attached to a peripheral framework, these sheets of metal serving to give the door great rigidity in the plane of the door. The door construction also includes fireproof sheets such as those made of asbestos for making the doors fire resistive and thus meeting the building code requirements of various cities.

My door may conveniently be made of wood or similar material, but it should be understood that metal may enter into its construction either partially or completely, providing a high sound resisting efliciency is obtained. The door may conveniently be constructed of an inner frame work 30 composed of a peripheral wood frame 10, and a peripheral wood frame 11 which may be'set in or dovetailed into the frame member 10, being secured thereto by glue 'or other suitable adhesive.

In order to give great rigidity to the door in 35 the plane of -the door, metal sheets 13 and 14 may be secured to the opposite faces of frame member 11 by means of bolts 15 which pass laterally through said sheets of metal and said frame member. The lower edges of sheets 13 and 14 are preferably bent at right angles to form flanges 16 and 1'1, respectively which lie flush on top of the frame member 10 and protect same from falling coals of fire in case of the destruction of the outer panels of the door by fire. In order to further prevent the passage of fire through the door, I provide a fireproof sheet 18, preferably of asbestos, which may be impregnated with sodium silicate, the latter also bein a fire resisting agent. The sodium silicate acts as an adhesive for firmly attaching the sheet 18 to one of the metal sheets 14. 'Animal glue or other suitable adhesive may be used instead of the sodium silicate, or the adhesive may be omitted entirely, if desired.

In order to further stiffen the door frame, suitable cleats or braces 20 are preferably provided above the flanges 1'7, being nailed in place by nails 21, or other suitable means. These braces serve to rigidly connect frame member 11 to the no frame members 10. Ordinary hinges 23 are attached to the frame member 10 and to the door jamb 24, which is of usual construction and fitted into the wall 25 surrounding the door. A threshold 26 is provided below the lower frame member 10, and the upper surface 27 of said threshold is preferably slightly tapered so that as the door closes, a resilient metal sealing strip 28 in the form of a pair of flexible, folded strips as shown in Fig. 5, gradually increases its pressure on the threshold 26 so as to make a tight fit and prevent the passage of sound between the lower frame 10 and said threshold. In contrast to other soundproof doors on the market which are so heavy as to require special hardware, locks, etc., my improved soundproof door requires only the ordinary lock 30, having a catch 31 operated by a door knob 32. The catch 31 engages in a suitable catch plate 33 secured to the door jamb. The lock 30 may be supported between reinforcing plates 33a if desired.

For the purpose of preventing the passage of sound through the door, I provide a pair of facing.

panels 35, one for each door face, these panels being preferably made of thin veneered wood so that they may be finished with stains and varnishes much the same as an ordinary wood door. However, these panels may be of light weight metal if desired. The soundproofness of my door depends almost entirely upon special spring clips 38. which serve to connect the panels 35 with the frame member 11. These spring clips are of sufficient resiliency and flexibility to absorb the vibration of the panels 35 due to impinging sound waves, but said clips are, however, of sufficient structural strength to support the weight of said panels 35. The clips 38 are preferably formed of a saddle section 39, connected by loops40 to outstanding flanges 41. Suitable screw holes 42 and 43 are provided in the saddle member 39 and flanges 41 respectively, for the purpose of receiving attaching screws 44 and bolts 15 respectively. The section 39 of the spring clip to an attaching block 46, and the ends of screws 45 are countersunk in the light weight panels 35, said screws 45 also being screwed into the attaching block46. Thus, the attaching strip 46 constitutes the connecting means between the panels 35 and the saddle section 39 of spring clips 38. The outstanding flanges 41 are connected to the metal plates 13 and 14 and to the frame member 11 by means of the bolts'l5 so that a resilient connection between the panels 35 and frame member 11 is secured by means of said spring clips 38. The steel or other metal for forming the clips 38 is preferably of suflicient thickness so that a load of 50 to 200 pounds is required to give the spring clip a permanent set. A steel having a high fatigue resistance to continued vibrations is also desirable so that the proper absorption of the sound waves impinging on panels 35 is obtained.

The door jamb 34 is preferably slightly tapered on the face adjacent the edge of the door so that the door moves into latched position to form a snug fit. A stop cleat 50 is provided around the inside of the door jamb 34 for the purpose of limiting the inward movement of said door. In order to make a close fit between the inner panel 35 of the door and the door stop 50 to prevent the passage of sound, I provide a flexible bumper 51 made of hollow rubber, or other suitable construction, which is inserted in a suitable recess formed in the stop 50. The outer surface of the bumper screws 44 connect the saddle" 51 extends slightly beyond the surface of the stop 50 so as to engage the panel 35 of the door and make a tight fit therewith, when the door is in closed position. It is desired to make a yielding contact between the peripheral edges of panels 35 and the frame member 10, and for this purpose a narrow strip of felt or other suitable fibrous material 53 is positioned between the outer edges of frame member 10 and the corresponding face of panels 35. A suitable adhesive preferably attaches the felt strip 53 to both the frame member 10 and the panels 35.

The type of door construction shown in Figs. 3 to 6, inclusive, is especially adapted for doors having a thickness of 4 inches or more but for doors having a thickness of 2" or less, it is preferable to have a slightly different arrangement of frame work and spring clips. In the thin form of door shown in Figs. '7 and 8, an outer peripheral frame member 55 of considerable width is provided, and

tongue and groove 57. The inner edges of frame member 55 are preferably provided with bevels 58, as shown in Fig. 8. veneered wood panels 59 and 60 are provided for the faces of the door, the panel 60 of which may be provided with a countersunk section 61 to give a. pleasing architectural appearance. Metal sheets 62 and 63 are secured to the frame member 56 by screws or nails 64. An asbestos sheet 65 may be adhesively secured to the inner face of each of the metal sheets 63, as in the door construction previously described, and the lower edges of the asbestos sheet 65 may extend downwardly below the lower edge of metal sheets 62 and 63, and then bent upwardly to form a section 67' for the purpose of catching any embers of fire from the wood panels. A separate sheet of asbestos 68 may extend downwardly be-v tween the frame member 55 and the face panels 59 and 60, so as to protect the lower portion of the door in case of fire.

It should be noted that in the door shown in Fig. 3, the spring clips are arranged around the periphery of the door back to back. In the thin type of door shown in Figs. 7 and 8, it is necessary to have a dilferent arrangement of clips in that the clips are arranged in pairs around the periphery of the door, as shown in Fig. 7. A suitable opening 70 is provided in the frame member 55 for each pair of clips, and the outstanding flanges 41 of the spring clips are secured to the frame member 55 around the periphery of this opening. The saddle members 39 of each spring clip then faces in a direction opposite to that of the saddle member of the adjacent spring clips, and each saddle member is provided with a wooden or other type of block 72 which is attached to its respective panels by suitable attaching means, such as screws 73. The heads of screws 73 are countersunk in the facing panels and a wooden plug 74 is provided for each screw head, said plug being capable of concealing the screw head and taking a suitable finish. Screws 73d pass through suitable holes in the saddle 39 and attach said saddle to the block 72.

My improved door has room to another. In testing the sound efficiency of a door, the loudness is measured in sensation units or decibels, and the difference between one side and the other, or the reduction, indicates the insulating value of the door. For the 2 inch door shown in Figs. 7 and 8, this reduction said frame work, a light factor proved to be 37 which was exactly equal to the reduction factor obtained for the complicated and heavy lead door previously described. My door is comparatively light in weight The weight for the 2 inch door in Figs. '7 and 8 is 125 pounds, whereas the aforementioned lead door has a weight of 425 pounds. Because of the light weight, I am enabled to use ordinary hardware for supporting the door in the door jamb, whereas the aforementioned lead door requires very heavy hinges and complicated locks and bolts. The cost of manufacture of my-soundproof door is comparatively low, so that its field of application is very wide.

I would state in conclusion that while the illustrated examples constitute practical embodiments of my invention, I do not wish to limit myself precisely to these details, since manifestly, the same may be considerably varied without departing from the spirit of the invention as defined in the appended claims.

Having thus described my invention, I claim as new and desire to secure by Letters Patent:

1. In a soundproof door construction, the combination with a door jamb, of a peripheral frame member adapted to approximately fit said door jamb, a metal sheet secured to the interior of said peripheral frame work, so as to give rigidity to weight panel in spaced parallel relation to each face of said metal sheet and frame work and out of direct contact therewith, and resilient spring clips yieldingly connecting said panels to said frame members so as to absorb the vibrations of said panels formed by impinging sound waves.

2. In a soundproof door construction, a frame member arranged around the periphery .of said door, a metal sheet secured to said frame member whereby rigidity of said frame member is obtained, a light weight panel in spaced parallel relation to said metal sheet and frame member and out of direct contact therewith, and spring clips yieldingly connecting said panel to said frame member for the purpose of absorbing vibrations of the panel due to impinging sound waves.

3. In a soundproof door construction, a frame member arranged around the periphery of said door, a metal sheet secured-to said frame member for providing stiffness to said frame member, a light weight panel in spaced parallel relation to said metal sheet and frame member and out of direct contact therewith, spring clips yieldingly connecting said panel to said frame member so as to absorb vibrations of said panel due to impinging sound waves, and fibrous connecting material between said panel and said frame member.

BRUNO E. BALDUF. 

